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M Osame

Publications and source records attributed to M Osame.

At least 523 records · Page 29Linked to original sources
PubMed1981

Freeze-fracture electronmicroscopic analysis of plasma membranes of cultured muscle cells in Duchenne dystrophy.

Depletion of intramembranous particles has been reported in the muscle fiber plasma membrane in Duchenne dystrophy. We searched for a similar abnormality in plasma membranes of cultured muscle cells obtained from six patients with Duchenne dystrophy and six controls. A precise method for phase microscopic to freeze-fracture electronmicroscopic correlation was devised to identify the cell of origin of each replicated membrane face. For both control and patient cells, P-face particle density was higher in myotubes than in mononuclear cells. However, there were no significant differences between control and dystrophic cells when comparing P faces of myotubes, E faces of myotubes, P faces of single cells, or E faces of single cells. The frequency distribution of particle diameters was similar in P faces of control and Duchenne myotubes. Other structural features of the freeze-fractured plasma membrane also were similar.

Adolescent↗
PubMed1980

Purification of acetylcholine receptors, reconstitution into lipid vesicles, and study of agonist-induced cation channel regulation.

We report the purification of acetylcholine receptors with active agonist-regulated cation channels from Torpedo californica electric organ tissue by five methods. In one method, previously used by others, contaminating proteins were removed from partially purified membranes by alkaline extraction, preserving membrane integrity throughout the procedure. In the other four methods, acetylcholine receptors were purified after solubalization with sodium cholate. The continual presence of soybean lipid in mixed micelles with cholate was required to prevent irreversible inactivation of the cation channel. Solubilized receptors were purified by affinity chromatography using either Naga naja siamensis toxin III or concanavalin A coupled to agarose. Sucrose gradient centrifugation was also used to purify solubilized receptors. The best method combined affinity chromatography on toxin-agarose and concanavalin A agarose. Receptors purified by all five methods were incorporated into soybean lipid vesicles by the cholate dialysis technique. The agonist-regulated cation channels of the receptors were equally active after reconstitution, independent of the method used for purification. All reconstituted vesicle preparations were similar in preferential orientation of acetylcholine receptor toward the external surface, dose-response to carbamylcholine, carbamylcholine-induced desensitization, and carbamycholine-induced influx of 22Na+ per mol of receptor. Carbamylcholine-induced 22Na+ influx/receptor was greater after reconstitution than in native vesicles. This was because, in native vesicles, carbamylcholine-induced 22Na+ influx was limited by equilibration of the internal volume of the vesicles with the external 22Na+ concentration, whereas in reconstituted vesicles 22Na+ influx was limited by desensitization of the receptor molecule. We demonstrate that only one of the two toxin binding sites on the receptor monomer, the one which can be affinity alkylated with 4-(N-maleimido)benzyltrimethylammonium, controls the carbamylcholine-induced opening of the cation channel.

Acetylcholine↗
PubMed1980

A case of nemaline myopathy with ophthalmoplegia and mitochondrial abnormalities.

A case of nemaline myopathy with ophthalmoplegia is reported. The patient was a 35-year-old man born of consanguineous parents. He had a myopathic face, high-arched palate, nasal voice, scoliosis, very thin trunk and marked muscle weakness involving face, neck, limbs and trunk. He also had ptotis of the left eyelid and mild bilateral ophthalmoplegia, also detected by electrooculogram. Biopsy of gastrocnemius muscle revealed nemaline rods. At the ultrastructural level, the rods appeared to have axial and cross striations, and in cross-sections at high magnification they seemed to have a crystal lattice structure. Intranuclear rods were also observed. In addition to the rods, abnormal mitochondria including a number of paracrystalline inclusions were seen.

Adult↗
PubMedDate not supplied

Morphometric analysis of intramuscular nerves.

Intramuscular nerves were obtained at autopsy from five adult controls and were morphometrically analyzed. The number of myelinated fibers was directly proportional to the diameter of the fascicles. The fascicles were grouped into six sizes according to diameter. For each group, the normal range of distribution of the number of myelinated fibers could be estimated. Fiber size distribution and myelinated fiber density were also calculated. A unimodal fiber size distribution was observed for the small fascicles (less than 50 microns in diameter), and a bimodal pattern was observed for the large fascicles. Total myelinated fiber density was high in the small fascicles, and it decreased as the fascicles became larger in size, approaching the values observed in the large peripheral nerves. This study will be helpful in objectively evaluating morphological changes of intramuscular nerves in adult neuromuscular disorders.

Adult↗
PubMedDate not supplied

Phenotypic Duchenne muscular dystrophy with C-terminal domain.

We report a patient with X-linked muscular dystrophy who had rapidly progressive muscle weakness and became wheelchair-bound at age 10 years. Clinically, he was diagnosed as having Duchenne muscular dystrophy; however, he was diagnosed as having Becker muscular dystrophy by dystrophin tests using a C-terminal monoclonal antibody. No immunolabelling was observed with a monoclonal antibody against the N-terminal domain. Multiplex polymerase chain reaction analysis revealed the deletion of exons 3-19. The data suggest that the deletion of the N-terminal domain of dystrophin can cause a severe phenotype even when the C-terminus of the protein is well preserved.

Adolescent↗
PubMedDate not supplied

Clinical course of HTLV-I-associated uveitis.

PURPOSE: To define the long-term clinical course and visual outcome of human T-cell lymphotrophic virus type I (HTLV-I)-associated uveitis (HAU). METHODS: We reviewed the clinical data on 96 eyes of 70 patients, 26 men and 44 women, with HAU, with specific reference to recurrence of the disease and long-term visual outcome. The mean follow-up period was 83 months (range, 12-276 months). RESULTS: The mean age of onset was 42.8 years (range, 7-78 years of age), with men presenting at a significantly younger age. Forty-seven patients had isolated HAU; in 10 patients, HTLV-I-associated myelopathy occurred before or after the onset of HAU; in 14 patients, hyperthyroidism had preceded HAU. A single episode of mild to moderate acute uveal inflammation with resolution in a few weeks or more occurred in 44 (62.9%) patients, and multiple episodes in 26 (37.1%), with a mean interval of 16 months (range, 1-250 months), which affected the same eye, fellow eye, or both. The majority of patients had favorable visual outcome at the last examination, whereas only a few patients suffered poor vision resulting from steroid cataract and retinochoroidal degeneration. CONCLUSIONS: The clinical course of HAU is virtually benign and its visual outcome is favorable, although its recurrence is common. The uveitis is usually isolated and affects a portion of otherwise unremarkable HTLV-I carriers, but it may sometimes be manifest as a symptom of syndromic diseases such as HTLV-I-associated myelopathy or hyperthyroidism. This study describes for the first time cases of HAU that occurred many years before manifestation of HTLV-I-associated myelopathy.

Adolescent↗